The impact of short-lived source gases

on the ozone layer under

the influence of a changing climate

A proposed contribution to G-SPARC

Björn-Martin Sinnhuber

Institute of Environmental Physics

University of Bremen

December 2006

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Very Short-Lived Source gases: The paradigm

from WMO (2003)

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Open issues

• What is the (current) contribution of very short-lived source

(VSLS) gases to stratospheric ozone depletion?

• How are VSLS transported through the tropical tropopause

layer (TTL) into the stratosphere?

• Rate of convective transport into the upper troposphere / lower

stratosphere

• Chemical degradation in the TTL

• Wet removal of degradation products from the TTL

• How will the contribution of VSLS change in a changing

climate?

• How will the (oceanic / biogenic) sources change?

• How will the transport processes (incl. wet removal) change?

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Future Considerations for Halogenated VSLS (WMO, 2007)

• Possible future changes in anthropogenic VSLS. If anthropogenic

emissions increased, or if presently unused halogenated VSL SGs

were to come into widespread commercial use, then halogenated

VSLS would become of increased importance in affecting the future

behavior of stratospheric ozone.

• Delivery of VSLS to the stratosphere may change in the future in

response to circulation changes. The impact of natural

halogenated VSLS might also be influenced by changes in the

atmospheric circulation, which could, for example, increase the rate of

delivery of VSL SGs and PGs into the stratosphere. 

• Natural VSLS emissions may respond to future changes in

climate processes. Natural sources could respond to changes in, for

example, CO2, land use, wind speed, and temperature.

Our knowledge about these potential effects, and many other

relevant feedbacks, is very limited at present.

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Context

addresses New SPARC Initiative 1 - Chemistry Climate

Interactions

is of direct relevance for the (next, 2010) WMO/UNEP Scientific

Assessment of Ozone Depletion

expands on previous work of our group

How will the emissions, transport, and effects of VSLS change in

a changing cimate ?

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Previous work / related activities

• Investigation of SCIAMACHY BrO observations

(Sinnhuber et al., GRL, 2005; Sheode et al., ACP(D), 2006;

Alexei Rozanov: „BOOST“ BrO intercomparison / validation project)

• Modelling studies on the impact of bromine from VSLS on past

stratospheric ozone trends

(Sinnhuber et al., ACP(D), 2006)

• Idealized model studies on transport of VSLS through the TTL

(Sinnhuber and Folkins, ACP, 2006)

• Validation of convective transport in global models

(SCOUT-O3 WP 6.2; Folkins et al., JGR, 2006)

• Investigation of oceanic phytoplankton from SCIAMACHY

observations

(Astrid Bracher: DFG project „PASAT“; HGF Nachwuchsgruppe)

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BrO „climatology“ from SCIAMACHY observations

DJF

JJA SON

MAM

fro

m S

he

od

e e

t a

l., A

CP

(D),

200

6

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SCIAMACHY BrO: Stratospheric bromine from VSLS

SCIAMACHY BrO observations

suggest present contribution of

~3ppt bromine from very short-

lived source gases.

SCIAMACHY BrO observations

suggest present contribution of

~3ppt bromine from very short-

lived source gases.

from WMO (2007), based on

Sinnhuber et al., GRL (2005)

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Impact of short-lived bromine on ozone trends

from Sinnhuber et al.,

ACPD (2006)

Additional bromine

from very short-lived

source gases has

significant impact on

calculated ozone

trends (in particular

for periods with

enhanced aerosol

loading).

Additional bromine

from very short-lived

source gases has

significant impact on

calculated ozone

trends (in particular

for periods with

enhanced aerosol

loading).

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Transport processes: Convective transport into the TTL

from Sinnhuber and

Folkins, ACP (2006)How will this respond to climate change

(e.g. changes in tropical SST and

tropospheric temperature) ?

How will this respond to climate change

(e.g. changes in tropical SST and

tropospheric temperature) ?

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Importance of wet removal in the TTL: Model calculations

from WMO (2007), based on

Sinnhuber and Folkins, ACP

(2006)

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Convective transport of VSLS: Model vs aircraft observations

from Sinnhuber and

Folkins, ACP (2006)

Observations of

VSLS very limited

at present.

Observations of

VSLS very limited

at present.

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Validation of modelled tropical tracer transport

Comparison of idealized tracers as

part of European IP SCOUT-O3.Large differences in

modelled short-lived

tracers between different

models.

Large differences in

modelled short-lived

tracers between different

models.

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Observation of oceanic source regions from SCIAMACHY

Oceanic bromoform emissions related to

phytoplankton (in particular diatoms, e.g.

see Quack et al., GRL, 2004).

Oceanic bromoform emissions related to

phytoplankton (in particular diatoms, e.g.

see Quack et al., GRL, 2004).

A. Bracher, DFG

project „PASAT“

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Suggested methodology

Analysis of SCIAMACHY BrO (plus NO2, O3, ...) observations for VSLS

(All going well there will be ~10 years of SCIAMACHY data by the end of the project)

Analysis of SCIAMACHY BrO (plus NO2, O3, ...) observations for VSLS

(All going well there will be ~10 years of SCIAMACHY data by the end of the project)

Process oriented model studies to investigate transport of VSLS through the TTL

•How will the transport processes (incl. wet removal) change for changes

in tropical SST ?

•Are the relevant processes adequately represented in current CCMs ?

Process oriented model studies to investigate transport of VSLS through the TTL

•How will the transport processes (incl. wet removal) change for changes

in tropical SST ?

•Are the relevant processes adequately represented in current CCMs ?

Investigate how oceanic VSLS emissions may change for changes in tropical SST

(e.g., investigate changes in plankton distribution and calculated air-sea fluxes as a result of ENSO)

Investigate how oceanic VSLS emissions may change for changes in tropical SST

(e.g., investigate changes in plankton distribution and calculated air-sea fluxes as a result of ENSO)

Full model calculations on the effect of VSLS in a changing climateFull model calculations on the effect of VSLS in a changing climate15

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Extra slides

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Very Short-Lived Source gases: The paradigm

from WMO (2007)(update from WMO, 2003)

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Validation of modelled tropical tracer transport

Bromoform - 20 day Methyl Iodine - 5 day

Comparison of idealized tracers in different CTMs and CCMs as part

of European IP SCOUT-O3.

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Chlorophyl concentration from MERIS

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Suggested methodology

• Investigation of stratospheric BrO (and NO2, O3, ...) from

SCIAMACHY observations

• All going well there will be ~10 years of SCIAMACHY

observations towards the end of the project

• Investigate transport processes of VSLS and their sensitivity to

climate change from a range of modelling tools

• How will the transport processes (incl. wet removal) change for

changes in tropical SST ?

• Are the relevant processes adequately represented in current

CCMs?

• Can we learn anything about changes in oceanic biogenic

production in a changing climate?

• Analysis of SCIAMACHY observations (plus other data)